Increasing demands for better fuel economy have lead to improvements and developments in hybrid vehicles, electric vehicles, and vehicles powered by fuel cells or diesel fuel. Efforts on the part of the automotive industry to increase fuel economy have included, but are not limited to, reductions in mass, improved aerodynamics, active fuel management, direct injection engines, homogeneous charge compression ignition engines, and hybrid engines. Still, other mechanisms, techniques, and energy sources that will improve fuel economy are continually being sought. To this end, the use of piezoelectric materials to harvest energy has received a great deal of attention in recent years. As is well known, the piezoelectric effect involves the conversion of mechanical strain into electric current or voltage. Many different sources could provide the requisite strain; e.g. human motion, seismic activity, vibrations, etc.
It is generally known that vehicles are subjected to vibrations, especially while being driven. These vibrations have typically been considered undesirable. In fact, a great deal of effort has gone into the development of suspension systems that include springs, dampers, shock absorbers, and the like, that provide vehicular stability and insulate the vehicle's passenger compartment from vibration caused by, for example, driving on bumpy or otherwise tortuous roadways. For example, resilient bumpers such as elastomeric jounce bumpers are typically used in vehicular suspension systems for cushioning impacts between two metallic members such as frame member and control arm. The jounce bumper is used to stiffen the suspension gradually as it approaches the end of its jounce travel. This cushions the impact, thus reducing noise and other undesirable consequences of the impact.
Currently, the energy associated with these vibrations is lost. However, harvesting and utilizing this energy would provide an additional source of energy that could be used to increase fuel economy. The ability to tap this additional source of energy while not compromising the benefits of modern vehicular suspension systems would greatly benefit both the automotive industry and their customers.